Vaccines alone will "not be enough" to beat the coronavirus and people will "have to adapt" their lifestyles and keep minimising contact with others to prevent it from spreading, a leading expert has warned.

Dr David Nabarro, the World Health Organisation's special envoy on COVID-19, told Sky News's Kay Burley that although "life has to go on", the public should continue wearing face masks and behave "carefully".

With the next target date for the relaxation of government restrictions in England still set for 21 June, he said: "I'm trying to again really reiterate that it can't be just about restrictions. The future for humanity is going to require that we adapt our lifestyles so that we make it hard for this virus to spread.

"We know that the virus is constantly changing, which means that although vaccination is a marvellous, marvellous asset, it's not going to be enough.

"We are going to have to continue to behave as though the virus is an ever-present threat."

Dr Nabarro warned that the coronavirus is still "very dangerous" and people must behave sensibly, adding: "The last thing any of us want is to have people needing to go on restricting their lives, but this virus has not gone away.

"In some ways, it's lurking and just waiting to strike again.

"So I want to suggest to everybody, please be really, really careful."

Dr Nabarro added: "It's really up to people everywhere to organise their lives to minimise the amount of contact they have with others, wear their face masks and just keep that protection going.

"It's not a big thing to do to mask yourself and we want to ask people to go on doing that and go on being careful because this virus is just very, very dangerous and it's very present."

Although Dr Nabarro is not opposed to restrictions being lifted, he said it was important people continued "behaving carefully because at school, at university, in the pub, in the restaurant, in the social club, the virus is still going to be around and it can come back with a huge surge very, very quickly".

Dr Nabarro added: "It's really up to people everywhere to organise their lives to minimise the amount of contact they have with others, wear their face masks and just keep that protection going.

"It's not a big thing to do to mask yourself and we want to ask people to go on doing that and go on being careful because this virus is just very, very dangerous and it's very present."

Although Dr Nabarro is not opposed to restrictions being lifted, he said it was important people continued "behaving carefully because at school, at university, in the pub, in the restaurant, in the social club, the virus is still going to be around and it can come back with a huge surge very, very quickly".

Ahead of the G7 summit in Cornwall, Dr Nabarro said he is hoping leaders will say "very clearly" they are "going to work together to make sure that the world is vaccinated adequately by the end of 2022".

After Boris Johnson made the pledge over the weekend, Dr Nabarro said: "That would be a gift to generations to come and is the kind of leadership that really we're expecting and hoping to see."

More than 40.5 million people have now had their first jab in the UK, over 28 million are fully vaccinated, and people aged 25-29 have been booking appointments in their hundreds of thousands since the programme opened up further earlier this week.

But there remains concern over the spread of the Indian variant, also known as the Delta variant, which has caused a spike in infections over the past week or so and led to uncertainty as to whether England's 21 June unlocking will go ahead as planned.